Conventionally, there is known a rotary compressor wherein, as described in Japanese Patent Laid-Open Publication No. 5-202874,a blade for partitioning a cylinder chamber into a suction chamber and a compression chamber is integrally provided in a protruding manner on a roller fitted on an eccentric portion of a drive shaft and is swingably supported in a receiving groove of a support body rotatably provided in the cylinder, whereby gaseous fluid is compressed through the rotation of the roller. More specifically, in the conventional rotary compressor, as shown in FIG. 1, a roller B provided with an integral blade B1 protruding radially outwardly from the roller is disposed in the cylinder chamber A1 of cylinder A which is fitted with a confronting front and rear heads on axially opposed sides so that upper and lower end faces of the roller B and blade B1 make a sliding contact with respective faces of the front and rear heads, and a circular pillar-shaped support body C making sliding contact with each head is rotatably supported in the cylinder. A tip portion of the blade B1 is supported on a receiving groove C1 formed in the support body C in such a manner that the blade B1 can swing and move back and forth. Thereby, the inner space of the cylinder chamber A1 is divided into the compression chamber X and the suction chamber Y by the roller B and blade B1. And, by fitting the roller B around the eccentric portion of the drive shaft and revolving the roller B within the cylinder chamber A1 by means of the drive shaft, gaseous fluid is sucked into the suction chamber Y and compressed in the compression chamber X.
In the above-described compressor, because the upper and lower end faces of the roller B and blade B1 are in sliding contact with the heads, it is necessary to lubricate the upper and lower end faces of the roller B and blade B1 with oil supplied thereto. For this purpose, conventionally, a high pressure lubrication oil supplied to sliding contact portions between the eccentric portion of the drive shaft and an inner peripheral surface of the roller B has been supplied there by utilizing a pressure difference between the inner peripheral side of the roller B and the suction chamber Y, a pressure difference between the inner peripheral side of the roller B and the compression chamber X, and a pressure difference between the compression chamber X and the suction chamber Y.
Namely, a pressure difference from the inner peripheral side of the roller B takes place in the suction chamber Y and even in the compression chamber X until the gaseous fluid is compressed to a predetermined pressure in the compression chamber X, and there also exists a pressure difference between the suction chamber Y and the compression chamber X. By utilizing these pressure differences, the high pressure lubrication oil having lubricated the interface between the eccentric portion and the roller B is introduced from the inner peripheral side of the roller B into the compression chamber X and the suction chamber Y via the upper and lower end faces of the roller B and from the compression chamber X into the suction chamber Y via the upper and lower end faces of the blade B1, as indicated by solid arrows n in FIG. 1, whereby the upper and lower end faces of the roller B and the blade B1 are lubricated.
In the conventional compressor, however, because the oil supply to the front and rear heads and to the upper and lower faces of the roller B and blade B1 in sliding contact with faces of the heads is made through clearances between these faces by utilizing the pressure differences, as described above, a pressure difference hardly occurs in hatched portions D and E in FIG. 1, namely, in upper and lower end face portions D at a blade protrusion base portion of the roller B from which the blade protrudes and upper and lower end face portions E on the tip side of the blade B1 entering into the receiving groove C1 of the support body C, and no flow of the lubricating oil takes place there. As a result, there exists a problem that the sliding contact portions of the end faces of the roller B and blade B1 with the faces of the heads cannot be securely lubricated, resulting in a decrease of reliability.